Typical completion sequences in the past involve running in an assembly of screens with a crossover tool and an isolation packer above the crossover tool. The crossover tool has a squeeze position where it eliminates a return path to allow fluid pumped down a work string and through the packer to cross over to the annulus outside the screen sections and into the formation through, for example, a cemented and perforated casing or in open hole. Alternatively, the casing could have telescoping members that are extendable into the formation and the tubular from which they extend could be cemented or not cemented. The fracture fluid, in any event, would go into the annular space outside the screens and get squeezed into the formation that is isolated by the packer above the crossover tool and another downhole packer or the bottom of the hole. When a particular portion of a zone was fractured in this manner the crossover tool would be repositioned to allow a return path, usually through the annular space above the isolation packer and outside the work string so that a gravel packing operation could then begin. In the gravel packing operation, the gravel exits the crossover tool to the annular space outside the screens. Carrier fluid goes through the screens and back into the crossover tool to get through the packer above and into the annular space outside the work string and back to the surface.
This entire procedure is repeated if another zone in the well needs to be fractured and gravel packed before it can be produced. Once a given zone was gravel packed, the production string is tagged into the packer and the zone is produced.
There are many issues with this technique and foremost among them is the rig time for running in the hole and conducting the discrete operations. Other issues relate to the erosive qualities of the gravel slurry during deposition of gravel in the gravel packing procedure. Portions of the crossover tool could wear away during the fracking operation or the subsequent gravel packing operation, if the zone was particularly long. If more than a single zone needs to be fractured and gravel packed, it means additional trips in the hole with more screens coupled to a crossover tool and an isolation packer and a repeating of the process. The order of operations using this technique was generally limited to working the hole from the bottom up. Alternatively, one trip multi-zone systems have been developed that require a large volume of proppant slurry through the crossover tool and that increases the erosion risk.
What the present invention addresses are ways to optimize the operation to reduce rig time and enhance the choices available for the sequence of locations where fracturing can occur. Furthermore, through a unique valve system, fracturing can occur in a plurality of zones in any desired order followed by operating another valve to place filter media in position of ports so that production could commence with a production string without having to run screens or a crossover tool into the well. These and other advantages of the present invention will be more readily apparent to those skilled in the art from the description of the various embodiments that are discussed below along with their associated drawings, while recognizing that the claims define the full scope of the invention.